Inducibility of lambda phage development in Escherichia coli mutants thermosensitive for DNA replication.

In a thermosensitive dnaZ mutant lysogenic for lambda, induction of the prophage development was provoked at the restrictive temperature. In dnaD strain, spontaneous release of lambda proceeded even at 43 degrees C, but distinct induction of the prophage development was not caused by a heat treatment. Similarly, shift up of growth temperature did not lead to induction of lambda in lysogens carrying thermosensitive mutation in dnaH function or DNA polymerase I. In dnaH mutant, multiplication of lambda-virulent phage proceeded normally at 43 degrees C.